Early Eocene climates from mid-latitude upland and high-latitude Arctic environments in Canada: insights from Palaeobotanical proxies
Abstract
The climate of the early Eocene has been reconstructed using palaeontological proxies and is characterized as globally warm with ice-free conditions prevailing at both poles. Early Eocene Arctic landmasses supported extensive forest ecosystems of primarily temperate biota, but also included thermophilic elements such as crocodilians and mesothermic taxodioid conifers and angiosperms. Early Eocene mid-latitude North America—from British Columbia to Colorado—supported a tropical biota at low elevations, but a mixed biota of temperate and thermophilic biota at higher palaeoelevations. The greenhouse world of the early Eocene was punctuated by multiple hyperthermal events—geologically short warming events such as the Paleocene-Eocene Thermal Maximum (PETM) and ETM2, which preceded the Early Eocene Climatic Optimum (EECO). These hyperthermals and the sustained warming of the EECO allowed thermophilic plants such as palms to periodically penetrate even further north. The Eocene forests of British Columbia and the Canadian Arctic share a suite of mostly temperate tree genera, with clear correlation between high-elevation mid-latitude and low-elevation high-latitude biomes and thermal regimes; nevertheless, they experienced pronounced differences in the annual distribution of solar radiation. Early Eocene warm polar winters that experienced no direct solar energy input, yet high equable temperature and precipitation, has proven challenging to reproduce with climate models, without invoking either unrealistically high atmospheric CO2, or a variety of other mechanisms such as an enhanced hydrological cycle. Using a compilation of data from palaeobotanical proxies from mid-latitude and high-latitude sites in Canada—principally British Columbia and Ellesmere and Axel Heiberg islands—we compare and contrast early Eocene climates between mid-latitude upland and high-latitude lowland Arctic regions in Canada. Furthermore, we compare palaeobotanical proxy data to existing climate models to address how well different proposed mechanisms and model outputs succeed in reproducing the proxy-based early Eocene climate of these regions.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMPP51E1179W
- Keywords:
-
- 3339 Ocean/atmosphere interactions;
- ATMOSPHERIC PROCESSESDE: 3344 Paleoclimatology;
- ATMOSPHERIC PROCESSESDE: 1620 Climate dynamics;
- GLOBAL CHANGEDE: 4936 Interglacial;
- PALEOCEANOGRAPHY